JP7164331B2 - light modulator - Google Patents

Description

The present invention relates to an optical modulation element.

Optical elements that change the transmission/reflection properties, phase, amplitude, polarization, intensity, path, etc. of light are utilized in various optical devices. Various structures of light modulators have been presented to control the aforementioned properties of light in a desired manner within an optical system. For example, optically anisotropic liquid crystals and MEMS (micro electromechanical system) structures that utilize micromechanical movements of light blocking/reflecting elements are commonly used in optical modulators. there is Recently, there have been attempts to utilize nanostructures that utilize the phenomenon of surface plasmon resonance with respect to incident light in optical devices.

U.S. Patent Application Publication No. 2016/0054599

A problem to be solved by the present invention is to provide an element (optical modulation element) that electrically modulates light.

Another problem to be solved by the present invention is to provide an element (optical modulation element) that modulates light using the surface plasmon resonance phenomenon.

The problem to be solved by the present invention is also to provide an optical modulation element comprising a plasmonic nano-antenna or an array thereof.

The problem to be solved by the present invention is also to provide an apparatus including the light modulation element.

According to one aspect of the present invention, a nano-antenna, a conductor arranged to face the nano-antenna, and a conductor arranged between the nano-antenna and the conductor a first dielectric layer disposed between the active layer and the conductor; and a dielectric layer disposed between the active layer and the nanoantenna. and signal applying means configured to independently apply electrical signals to at least two of the nano-antenna, the active layer and the conductor. is provided.

The signal applying means may be configured to apply a first voltage to the conductor and a second voltage to the nanoantenna.

The signal applying means includes first voltage applying means for applying the first voltage between the conductor and the active layer, and the second voltage between the active layer and the nanoantenna. and a second voltage applying means for applying the

The signal applying means may be configured to apply a first voltage to the conductor, a second voltage to the active layer, and a third voltage to the nanoantenna.

The signal applying means may be configured to apply a first voltage to the conductor, a second voltage to the active layer, and a third voltage to the nanoantenna. At least one of the first voltage and the third voltage may be different from the second voltage.

The second voltage is also a reference voltage for the first voltage and the third voltage.

The second voltage is optionally also ground voltage.

The active layer includes a first charge density change region and a second charge density change region induced by an electrical signal of the signal applying means, the first charge density change region adjacent to the first dielectric layer. and the second charge density varying region may be provided adjacent to the second dielectric layer.

The conductor is also a back reflector electrode located under the active layer.

Said conductor is also a metal layer.

The active layer may also be a first active layer, and a second active layer in electrical contact with the conductor may be further provided between the conductor and the first dielectric layer.

between the first dielectric layer and the second dielectric layer, at least two active layers are provided in order from the first dielectric layer, and an intermediate dielectric layer is provided between the at least two active layers may be provided.

The active layer may have a multilayer structure including a lower layer and an upper layer. The lower layer and the upper layer may contain different materials or have different doping characteristics.

A plurality of the conductors may be spaced apart from each other, a plurality of the nanoantennas may be spaced apart from each other, and the active layer may be provided between the plurality of conductors and the plurality of nanoantennas. good.

Different voltages may be applied to at least two of the plurality of conductors, and different voltages may be applied to at least two of the plurality of nano-antennas.

A voltage may be independently applied to each of the plurality of conductors, and a voltage may be independently applied to each of the plurality of nano-antennas.

The plurality of conductors includes a first conductor and a second conductor, and the plurality of nanoantennas includes a first nanoantenna corresponding to the first conductor and a second nanoantenna corresponding to the second conductor. a nanoantenna, wherein a first voltage is applied to the first conductor, independently a second voltage is applied to the first nanoantenna, and a third voltage is applied to the second conductor; Independently, a fourth voltage is also applied to the second nanoantenna.

The conductor, the first dielectric layer, the active layer, the second dielectric layer, and the nano-antenna may constitute one unit element, and the light modulation element may be composed of a plurality of the unit elements. It can have an ordered structure.

The plurality of unit elements may be arranged one-dimensionally or two-dimensionally.

One nano-antenna may be arranged corresponding to one conductor, or a plurality of nano-antennas may be arranged for one conductor.

The active layer may include an electro-optic material whose permittivity is changed by an electrical signal applied thereto.

The active layer may include at least one of a transparent conductive oxide and a transition metal nitride.

At least one of the first dielectric layer and the second dielectric layer may include at least one of an insulating silicon compound and an insulating metal compound.

The light modulating element is also an element configured to induce phase modulation of light reflected by the nanoantenna.

The light modulation element may be configured to change the reflection phase of incident light up to 360°.

According to another aspect, there is provided an optical device including the light modulation element described above.

The optical device may be configured to steer the beam in one or two dimensions using the light modulating elements.

For example, the optical device may include at least one of a LIDAR (light detection and ranging) device, a 3D image acquisition device, a holographic display device, and a structured light generation device.

According to another aspect, a plurality of conductive elements spaced apart from each other; a plurality of nanoantennas positioned opposite the plurality of conductive elements; and the plurality of conductive elements and the plurality of nanoantennas. A voltage is independently applied to an active layer, which is arranged between and separated from them and whose physical properties are changed by an applied voltage, each of the plurality of conductive elements, and each of the plurality of nanoantennas. and voltage applying means configured to apply voltages independently applied to each of the plurality of conductive elements to cause charge concentration changes occurring in the first region of the active layer and the plurality of nanometers. A light modulation element is provided that modulates incident light by utilizing charge density changes that occur in the second region of the active layer due to voltages that are independently applied to the respective antennas.

The voltage applying means is configured to apply different voltages to at least two of the plurality of conductive elements and independently apply different voltages to at least two of the plurality of nano-antennas. may

The plurality of conductive elements includes a first conductive element and a second conductive element, and the plurality of nanoantennas includes a first nanoantenna corresponding to the first conductive element and a second nanoantenna corresponding to the second conductive element. nanoantennas, wherein the voltage applying means is configured to independently apply a voltage to each of the first conductive element, the first nanoantenna, the second conductive element and the second nanoantenna. good.

The optical modulation element includes a first insulating layer provided between the plurality of conductive elements and the active layer, and a second insulating layer provided between the plurality of nano-antennas and the active layer. and may further include.

The plurality of nanoantennas may be arranged in a one-dimensional manner, and the light modulation element may be configured to steer beams in a one-dimensional direction.

The plurality of nanoantennas may be arranged two-dimensionally, and the light modulation elements may be configured to steer beams in two-dimensional directions.

According to another aspect, there is provided an optical device including the light modulation element described above.

The optical device may be configured to steer the beam in one or two dimensions using the light modulating elements.

The optical device may include, for example, at least one of a lidar (LiDAR) device, a 3D image acquisition device, a holographic display device, and a structured light generation device.

According to the present invention, an element (optical modulation element) that electrically modulates light can be implemented. Also, it is possible to implement a device (optical modulation device) that modulates light using the surface plasmon resonance phenomenon. Also, an optical modulation device including a plasmonic nano-antenna or an array thereof can be implemented. Also, it is possible to implement an optical modulator that increases optical modulation efficiency and reduces noise. In addition, it is possible to implement an optical modulator capable of increasing the amount of change in the reflection phase. Also, it is possible to implement an optical modulator that reduces the amount of change in reflectance.

Furthermore, various optical devices having excellent performance can be implemented by applying the light modulation device.

FIG. 4 is a cross-sectional view showing an optical modulation element according to one embodiment; FIG. 10 is a cross-sectional view showing an optical modulation element according to another embodiment; FIG. 5 is a cross-sectional view showing an optical modulation element according to a comparative example; 4 is a graph showing phase changes of reflected light according to voltage application conditions of an optical modulation element (the element of FIG. 3) according to a comparative example; 4 is a graph showing changes in reflectance according to voltage application conditions of an optical modulation element (the element of FIG. 3) according to a comparative example; 4 is a graph showing phase changes of reflected light according to voltage application conditions of the light modulation device (the device shown in FIG. 1) according to the embodiment. 4 is a graph showing changes in reflectance according to voltage application conditions of the light modulation element (the element of FIG. 1) according to the embodiment. FIG. 10 is a cross-sectional view showing an optical modulation element according to another embodiment; FIG. 10 is a cross-sectional view showing an optical modulation element according to another embodiment; FIG. 10 is a cross-sectional view showing an optical modulation element according to another embodiment; FIG. 10 is a cross-sectional view showing an optical modulation element according to another embodiment; FIG. 10 is a cross-sectional view showing an optical modulation element according to another embodiment; FIG. 10 is a cross-sectional view showing an optical modulation element according to another embodiment; FIG. 11 is a perspective view showing an optical modulator according to another embodiment; FIG. 11 is a perspective view showing an optical modulator according to another embodiment; FIG. 11 is a perspective view showing an optical modulator according to another embodiment; FIG. 10 is a cross-sectional view showing an optical modulation element according to another embodiment; FIG. 10 is a cross-sectional view showing an optical modulation element according to another embodiment; FIG. 3 is a perspective view showing the structure/morphology of a nano-antenna applied to an optical modulation element according to an embodiment; FIG. 3 is a perspective view showing the structure/morphology of a nano-antenna applied to an optical modulation element according to an embodiment; FIG. 3 is a perspective view showing the structure/morphology of a nano-antenna applied to an optical modulation element according to an embodiment; FIG. 3 is a perspective view showing the structure/morphology of a nano-antenna applied to an optical modulation element according to an embodiment; 1 is a conceptual diagram illustrating a beam steering device including a light modulating element according to one embodiment; FIG. FIG. 4 is a conceptual diagram for explaining a beam steering element including an optical modulation element according to another embodiment; FIG. 2 is a block diagram for explaining an overall system of an optical device including a beam steering element to which an optical modulation element is applied according to one embodiment; 1 is a conceptual diagram showing a case where a lidar (LiDAR) device including a light modulation element according to an embodiment is applied to a vehicle; FIG. 1 is a conceptual diagram showing a case where a lidar (LiDAR) device including a light modulation element according to an embodiment is applied to a vehicle; FIG.

Hereinafter, an optical modulation element, an operation method thereof, and an apparatus including the optical modulation element according to an embodiment will be described in detail with reference to the accompanying drawings. The widths and thicknesses of layers and regions illustrated in the accompanying drawings may be exaggerated for clarity of the specification and convenience of explanation. Like reference numbers refer to like components throughout the detailed description.

FIG. 1 is a cross-sectional view showing an optical modulation element according to one embodiment.

Referring to FIG. 1, a conductor C10 and a nano-antenna N10 arranged to face it may be provided. Nano-antenna N10 can be said to be a plasmonic nano-antenna. An active layer A10 may be provided between the conductor C10 and the nanoantenna N10. The active layer A10 is also a layer whose physical properties change according to its electrical conditions. For example, at least one physical property of the active layer A10 changes depending on the voltage applied thereto. The permittivity of the active layer A10 changes depending on the electrical conditions (eg, applied voltage) related to the active layer A10 and its surrounding area. The change in the dielectric constant of the active layer A10 is also caused by the change in charge concentration (charge density) in the region inside the active layer A10. In other words, the dielectric constant of the active layer A10 changes due to the charge density change in the region inside the active layer A10. A first dielectric layer D10 may be disposed between the conductor C10 and the active layer A10. A second dielectric layer D20 may be disposed between the active layer A10 and the nanoantenna N10. The first dielectric layer D10 is also a first insulating layer that electrically separates the conductor C10 and the active layer A10, and the second dielectric layer D20 electrically separates the active layer A10 and the nanoantenna N10. It is also the second insulating layer for

The light modulation element according to this embodiment may include signal applying means configured to independently apply electrical signals to at least two of the nano-antenna N10, the active layer A10 and the conductor C10. The signal applying means may be configured to independently apply a voltage to each of the conductor C10 and the nanoantenna N10. For example, the signal applying means includes a first voltage applying means V B for applying a first voltage between the conductor C10 and the active layer A10, and a first voltage applying means V _B for applying a first voltage between the active layer A10 and the nanoantenna N10. A second voltage applying means _VT for applying two voltages may be included. At this time, the active layer A10 may be grounded.

The active layer A10 may include a first charge density changing region 10 in which the charge density changes according to the voltage applied between the conductor C10 and the active layer _A10 by the first voltage applying means VB. In addition, the active layer A10 may include a second charge density change region 20 in which the charge density changes according to the voltage applied between the active layer A10 and the _nanoantenna N10 by the second voltage applying means VT. The first charge density change region 10 may be provided adjacent to the first dielectric layer D10, and the second charge density change region 20 may be provided adjacent to the second dielectric layer D20. The first charge density change region 10 and the second charge density change region 20 are independently controlled.

The nano-antenna N10 converts light of a specific wavelength (or frequency) (incident light, visible electromagnetic waves and invisible electromagnetic waves) into the form of localized surface plasmon resonance. and captures that energy and can be said to be a nanostructured antenna for light. Nanoantenna N10 is also a conductive layer pattern (eg, a metal layer pattern) that also contacts a non-conductive layer (eg, a dielectric layer). Plasmon resonance can occur at the interface between the conductive layer pattern and the non-conductive layer (eg, dielectric layer). At this time, the non-conductive layer (eg, dielectric layer) is also provided on the second dielectric layer D20 or a layer separate from the second dielectric layer D20. For convenience, the conductive layer pattern itself will be described as the nano-antenna N10 below. The interface at which surface plasmon resonance occurs, such as the interface between the conductive layer pattern and the non-conductive layer (e.g., dielectric layer), is commonly referred to as a "metasurface" or "metastructure." can.

The nanoantenna N10 can also be made of a conductive material and have sub-wavelength dimensions. Here, sub-wavelength means a dimension smaller than the operating wavelength of nanoantenna N10. At least one of the dimensions that define the shape of the nanoantennas N10, such as thickness, width, length, or spacing between nanoantennas N10, or the array period of the nanoantennas (i.e., the sum of the length or width and the spacing). Either one can have sub-wavelength dimensions. The resonant wavelength also varies depending on the shape and size of the nanoantenna N10. The operating wavelength is about 1,550 nm, and the array period (an example of the sub-wavelength) of the nanoantenna is about 500 nm, but it is only an example, and the present application is limited thereto. not a thing

As a conductive material forming the nano-antenna N10, a highly conductive metal material capable of generating surface plasmon excitation is used. For example, at least one metal selected from a group consisting of Cu, Al, Ni, Fe, Co, Zn, Ti, Ru, Rh, Pd, Pt, Ag, Os, Ir, Au, etc. is employed. , and an alloy containing at least one of them. The nanoantenna N10 is a thin film in which metal nanoparticles such as Au and Ag are dispersed, carbon nanostructures such as graphene and CNT (carbon nanotube); poly(3,4-ethylenedioxythiophene) (PEDOT); Conductive polymers such as polypyrrole (PPy) and poly(3-hexylthiophene) (P3HT) may be included, or conductive oxides and the like may be included.

The active layer A10 is a layer whose physical properties change according to the electrical conditions applied thereto, and at the same time, it can perform the function of an electrode. For example, the active layer A10 is also a layer whose dielectric constant changes depending on electrical conditions. The electric field applied to the active layer A10 changes the charge concentration (charge density) in the region inside the active layer A10, thereby changing the dielectric constant of the active layer A10. For example, the active layer A10 includes ITO (indium tin oxide), IZO (indium zinc oxide), AZO (aluminum doped zinc oxide), GZO (gallium doped zinc oxide), AGZO (aluminum gallium zinc oxide), GIZO (gallium indium zinc oxide), It may also include a transparent conductive oxide (TCO), such as a transparent conductive oxide (TCO). Alternatively, it may include transition metal nitrides such as TiN, ZrN, HfN, TaN. Others may include electro-optic (EO) materials that change their effective dielectric constant when an electrical signal is applied. The electro-optic materials include, for example, crystalline materials such as LiNbO ₃ , LiTaO ₃ , potassium tantalate diobate (KTN), lead zirconate titanate (PZT), or various polymers with electro-optic properties. may include

The dielectric constant of the active layer A10 also changes depending on the wavelength. A relative permittivity _εr to the vacuum permittivity ε0 is called a dielectric constant, and the real part of the dielectric constant of the active layer A10 can show a value of ₀ in a predetermined wavelength band. . A wavelength band in which the real part of the dielectric constant has a value of 0 or very close to 0 is called an ENZ (epsilon near zero) wavelength band. The dielectric constant of most materials is a function of wavelength and is also expressed as a complex number. The dielectric constant of a vacuum is 1, and the real part of the dielectric constant is a positive number greater than 1 for general dielectrics. For metals, the real part of the dielectric constant can also be negative. The dielectric constant of most materials has a value greater than 1 in most wavelength bands, but the real part of the dielectric constant can have a value of 0 at a specific wavelength. It is known to exhibit peculiar optical properties when the real part of the dielectric constant has a value of zero or very close to zero. The optical modulation element of one embodiment can set the operating wavelength band to a region including the ENZ wavelength band of the active layer A10. By setting the resonance wavelength band of the nano-antenna N10 and the ENZ wavelength band of the active layer A10 to be similar, it is possible to expand the range in which the optical modulation performance is adjusted. The ENZ wavelength band of the active layer A 10 also differs depending on the characteristics (charge densities) of the first charge density change region 10 and the second charge density change region 20 .

The conductor C10 includes a conductive material and may function as an electrode. The conductive material of conductor C10 is the same as or similar to the conductive material of nanoantenna N10. For example, the conductor C10 may include at least one selected from a group consisting of Cu, Al, Ni, Fe, Co, Zn, Ti, Ru, Rh, Pd, Pt, Ag, Os, Ir, Au, and the like. metals, including alloys comprising at least one of them. Alternatively, the conductor C10 is a thin film in which metal nanoparticles such as Au and Ag are dispersed; carbon nanostructures such as graphene and CNT; poly(3,4-ethylenedioxythiophene) (PEDOT), polypyrrole (PPy) , a conductive polymer such as poly(3-hexylthiophene) (P3HT), or may include a conductive oxide or the like.

Conductor C10 is also a back reflector electrode located below active layer A10. Therefore, the conductor C10 can function as an electrode while reflecting light. The conductor C10 is optically coupled with its corresponding nanoantenna N10, and light can be reflected by the optical interaction between the nanoantenna N10 and the conductor C10. 8 to 18, which will be described later, all conductors (conductive elements) corresponding to the conductor C10 in FIG. 1 are also lower reflector electrodes.

The first dielectric layer D10 and the second dielectric layer D20 may include an insulating material (dielectric material). At least one of the first dielectric layer D10 and the second dielectric layer D20 may include at least one of an insulating silicon compound and an insulating metal compound. The insulating silicon compound includes, for example, silicon oxide (SiO _x ), silicon nitride (Si _x N _y ), silicon oxynitride (SiON), etc. The insulating metal compound includes, for example, aluminum oxide. (Al ₂ O ₃ ), hafnium oxide (HfO), zirconium oxide (ZrO), hafnium silicon oxide (HfSiO), and the like. However, the specific materials of the first dielectric layer D10 and the second dielectric layer D20 presented here are exemplary and not limited thereto. The first dielectric layer D10 and the second dielectric layer D20 may be made of the same material or may have different material compositions.

Voltages are applied independently between the active layer A10 and the conductor C10 and between the active layer A10 and the _nanoantenna N10 using the first voltage applying means VB and the second voltage applying means _VT . can do. When the active layer A10 is grounded, that is, when the voltage of the active layer A10 is 0 V, the voltage applied to the conductor _C10 by the first voltage applying means VB is also a positive (+) voltage, It is also a negative (-) voltage. When the voltage applied to the conductor C10 is a positive (+) voltage, the first charge concentration change region 10 is also a charge accumulation region, and the voltage applied to the conductor C10 is negative (- ), the first charge concentration change region 10 is also a charge depletion region. In some cases, a voltage of 0 V can also be applied to the conductor C10. Also, the voltage applied to the nano-antenna _N10 by the second voltage applying means VT is both a positive (+) voltage and a negative (-) voltage. When the voltage applied to the nanoantenna N10 is a positive (+) voltage, the second charge concentration change region 20 is also a charge accumulation region, and when the voltage applied to the nanoantenna N10 is a negative (-) voltage. In some cases, the second variable charge concentration region 20 is also a charge depletion region. Optionally, a voltage of 0V can also be applied to the nanoantenna N10.

In order to independently adjust the voltages applied to the conductor C10 and the nanoantenna N10, the characteristics of the first charge density change region 10 and the second charge density change region 20 can be independently controlled. Therefore, one of the first charge density change region 10 and the second charge density change region 20 is also a charge accumulation region and the other is a charge depletion region. Alternatively, both the first charge density change region 10 and the second charge density change region 20 are both the charge accumulation region and the charge depletion region. Even if both the first charge density change region 10 and the second charge density change region 20 are charge accumulation regions and charge depletion regions, their charge densities are controlled differently.

If the majority carriers of the active layer A10 are negative (-) charges, in other words if the active layer A10 is an N-type electrode or an N-doped material layer, the conductor C10 If the voltage applied to is a positive (+) voltage, the first charge density change region 10 is also an electron accumulation region, and if it is a negative (-) voltage, the first charge density change region 10 is also the electron depletion region. Similarly, if the voltage applied to the nanoantenna N10 is a positive (+) voltage, the second charge concentration change region 20 is also an electron accumulation region, and if it is a negative (-) voltage, , the second charge density change region 20 is also an electron depletion region. Optionally, the majority carriers in active layer A10 are also positive (+) charges. In other words, the active layer A10 is either a P-type electrode or a P-doped material layer. In that case, if the voltage applied to the conductor C10 is a positive (+) voltage, the first charge density change region 10 is also a hole depletion region, and if it is a negative (-) voltage, The first charge density change region 10 is also a hole accumulation region. Similarly, if the voltage applied to the nanoantenna N10 is a positive (+) voltage, the second charge concentration change region 20 is also a hole depletion region, and if it is a negative (-) voltage, For example, the second charge density change region 20 is also a hole accumulation region.

The conductor C10 can be said to be a first gate electrode, and the nano-antenna N10 can be said to be a second gate electrode. The first dielectric layer D10 can be said to be a first gate insulation layer, and the second dielectric layer D20 can be said to be a second gate insulation layer. The voltage applied to conductor C10 can be referred to as a first gate voltage, and the voltage applied to nanoantenna N10 can be referred to as a second gate voltage. From the aspect that the first gate voltage and the second gate voltage are controlled independently of each other, it can be said that the light modulation element of this embodiment has a double electrode structure (double gate electrode structure).

The characteristics of the first charge density change region 10 and the second charge density change region 20 can be independently controlled using the first voltage application means _VB and the second voltage application means _VT , thereby The optical modulation characteristics of the elements are also different. The light modulation properties are controlled by changing the properties of the active layer A10 and the electro-optical interaction between the nanoantenna N10, the active layer A10 and the conductor C10. For example, when a given incident light LI is reflected by the _nanoantenna N10, the characteristics of the reflected light _LR also change depending on the characteristics of the first charge density change region 10 and the second charge density change region 20. FIG. In other words, the characteristics of the reflected light _LR also differ depending on the voltage applied to the conductor C10 by the first voltage applying means VB and the voltage applied to the nano _- antenna _N10 by the second voltage applying means VT. Independent control of the characteristics of the first charge density change region 10 and the characteristics of the second charge density change region 20 can greatly improve the light modulation characteristics and reduce problems such as noise. This will be described in more detail later with reference to FIGS. 6 and 7 and the like.

In FIG. 1, the "signal applying means" for applying an electrical signal to the light modulation element is a first voltage applying means VB connected between the conductor C10 and the active layer _A10 , and the active layer A10. Although the active layer _A10 includes the second voltage applying means VT connected between the nano-antenna N10 and is grounded, the configuration of such signal applying means may be different. An example is shown in FIG.

FIG. 2 is a cross-sectional view showing an optical modulator according to another embodiment.

Referring to FIG. 2, the signal applying means for applying an electrical signal to the light modulation element is configured to apply voltages independently to the conductor C10, the active layer A10, and the nanoantenna N10. good too. The signal applying means includes a first voltage applying means V1 for applying a first voltage to the conductor C10, a second voltage applying means V2 for applying a second voltage to the active layer A10, and a nano antenna N10. A third voltage applying means V3 for applying a third voltage may be included. Here, the first voltage may be higher or lower than the second voltage. Also, the third voltage may be higher or lower than the second voltage. Optionally, at least one of the first voltage and the third voltage may be the same as the second voltage. The second voltage is also the reference voltage for the first voltage and the third voltage. The second voltage is optionally also a ground voltage. In that case, in FIG. 1, it is similar to the case where the active layer A10 is grounded.

By independently applying voltages to the conductor C10, the active layer A10, and the nanoantenna N10, the characteristics of the first charge density change region 10 and the second charge density change region 20 are independently controlled by the potential difference between them. can be controlled by

FIG. 3 is a cross-sectional view showing an optical modulator according to a comparative example.

Referring to FIG. 3, the light modulation device according to the comparative example may have a nano-antenna N1 on the conductor C1, an active layer A1 in contact with the conductor C1, and the active layer A1 and the nano-antenna N1. may also include a dielectric layer D1 provided between. The optical modulation element according to the comparative example also includes voltage application means V for applying voltage to the nano-antenna N1 with respect to the conductor C1. A voltage applying means V is connected between the conductor C1 and the nanoantenna N1, and the conductor C1 is grounded.

In this case, one charge density change region 1 is formed in the active layer A1 by the voltage applied between the conductor C1 and the nanoantenna N1 by the voltage application means V. FIG. Charge density change region 1 is formed adjacent to dielectric layer D1. Such a light modulation element can be said to have a single gate electrode structure.

FIG. 4 is a graph showing the phase change of the reflected light according to the voltage application conditions of the light modulation device (the device shown in FIG. 3) according to the comparative example.

Referring to FIG. 4, the reflection phase (°) varies depending on the voltage, and the reflection phase (°) varies up to about 270° and is difficult to vary further. Therefore, there is a limitation that all phases cannot be represented. Such a critical point induces a problem of increased noise in light wave steering, ie beam steering.

FIG. 5 is a graph showing changes in reflectance according to voltage application conditions of an optical modulation element (the element shown in FIG. 3) according to a comparative example.

Referring to FIG. 5, it can be seen that the reflectance (%) varies greatly depending on the voltage. Since the reflectance (%) is different for each voltage, the wavefront of the generated light wave is distorted. The result is increased noise in light wave steering. The more noise, the less energy in the main lobe, the shorter the monitoring distance, and the light reflected by the beam steered in undesired directions can lead to information distortion. put away. Such change in reflectance (%) may occur because the amplitude also changes when the phase of the reflected wave changes.

FIG. 6 is a graph showing phase changes of reflected light according to voltage application conditions of the light modulation device (the device shown in FIG. 1) according to the embodiment.

Referring to FIG. 6, in one embodiment, since voltages can be applied independently to the upper _nanoantenna N10 and the lower conductor C10, the horizontal axis represents the upper voltage VT and the lower voltage VT. It is displayed in combination with the voltage _VB . According to one embodiment, the voltage condition can change the reflection phase (°) by 360°. It is compared with the comparative example of FIG. 4 where the reflection phase (°) varies up to 270°.

FIG. 7 is a graph showing changes in reflectance according to voltage application conditions of the light modulation element (the element shown in FIG. 1) according to one embodiment.

Referring to FIG. 7, the reflectance (%) is generally kept constant while the reflection phase (°) is changed according to the voltage condition. For example, within the measurement range, the amount of change in reflectance (%) is also within about ±15%. It is compared with the comparative example in FIG. 5 where the reflectance (%) varies greatly. It can also be seen that the average reflectance (%) in FIG. 7 is clearly higher than the maximum reflectance (%) in FIG.

6 and 7, according to one embodiment, the reflection phase (°) can be varied up to 360° and the reflectance (%) remains generally constant, When the light wave is steered, the efficiency is increased, the noise is reduced, and the distortion is suppressed. In particular, it is advantageously applied to the constant amplitude method, the 2π (360°)-full cover method, and the phase-only modulation method.

FIG. 8 is a cross-sectional view showing an optical modulator according to another embodiment.

Referring to FIG. 8, the light modulation device may further include a second active layer A20 electrically contacting the conductor C10 between the conductor C10 and the first dielectric layer D10. At this time, the active layer A10 between the first dielectric layer D10 and the second dielectric layer D20 can be called a first active layer A10. The second active layer A20 is made of the same or similar material as the first active layer A10. The second active layer A20 may include a third charge density changing region 30 whose charge density changes according to the voltage applied between the conductor C10 and the first active layer _A10 by the first voltage applying means VB. good. The third charge density change region 30 may be arranged adjacent to the first dielectric layer D10. In this embodiment, the first voltage _applying means VB induces a first charge density change region 10 in the first active layer A10 and a third charge density change region 30 in the second active layer A20. , the second voltage _applying means VT induces a second charge density change region 20 in the first active layer A10. The rest of the structure is the same as or similar to that of FIG. 1 except that the second active layer A20 including the third charge density change region 30 is further provided.

In this embodiment, the characteristic changes of the three charge density changing regions 10, 20 and 30 are used for optical modulation, which is advantageous for improvement and control of optical modulation characteristics.

FIG. 9 is a cross-sectional view showing an optical modulator according to another embodiment.

Referring to FIG. 9, at least two active layers may be provided between the first dielectric layer D10 and the second dielectric layer D20. Here, a case in which two active layers A11 and A12 are provided is illustrated. The two active layers A11 and A12 can be referred to as a first active layer A11 and a second active layer A12, respectively. An intermediate dielectric layer D15 may be provided between two adjacent active layers A11 and A12. The first active layer A11 and the second active layer A12 are made of the same or similar material as the active layer A10 of FIG. It is also made of the same or similar material as the body layer D20. The first active layer A11 and the second active layer A12 are made of the same material or different materials.

The light modulation element according to this embodiment includes a first voltage applying means V10 for applying a voltage to the conductor C10, a second voltage applying means V20 for applying a voltage to the first active layer A11, and a second active layer A12. and a fourth voltage applying means V40 for applying a voltage to the nanoantenna N10. Therefore, voltages can be applied independently to the conductor C10, the first active layer A11, the second active layer A12, and the nanoantenna N10. Optionally, one of the first active layer A11 and the second active layer A12 may be grounded.

A first charge density change region 11 and a second charge density change region 21 are formed in a lower region and an upper region of the first active layer A11, respectively. Similarly, a third charge density change region 31 and a fourth charge density change region 41 are formed in the lower region and the upper region of the second active layer A12, respectively. The potential difference between the conductor C10 and the first active layer A11 forms the first charge density change region 11, and the potential difference between the first active layer A11 and the second active layer A12 forms the second charge density change region 21 and the second active layer A12. A third charge density change region 31 is formed, and a fourth charge density change region 41 is formed by a potential difference between the second active layer A12 and the nanoantenna N10.

This embodiment is advantageous in improving and controlling the optical modulation characteristics because the characteristic changes of the four charge density changing regions 11, 21, 31, and 41 are used for optical modulation. Although not shown, three or more active layers may be used between the first dielectric layer D10 and the second dielectric layer D20, with an intermediate dielectric layer applied between them. can do.

FIG. 10 is a cross-sectional view showing an optical modulator according to another embodiment.

Referring to FIG. 10, one active layer A15 may have a multi-layer structure. For example, the active layer A15 may have a multilayer structure including a lower layer A15a and an upper layer A15b. The lower layer A15a and the upper layer A15b may contain different materials or have different doping characteristics. A first charge density change region 15 is formed in the lower layer A15a, and a second charge density change region 25 is formed in the upper layer A15b. When the materials of the lower layer A15a and the upper layer A15b are different or have different doping characteristics, the characteristics of the first charge concentration change region 15 and the second charge concentration change region 25 are similar to those of the first charge concentration change region of FIG. Region 10 and second charge density change region 20 are controlled differently. Optionally, the active layer A15 may have a multi-layer structure of three layers or more. Except for the fact that the active layer A15 has a multi-layer structure, the rest of the structure is the same as or similar to that of FIG. The active layer A15 of FIG. 10 can be applied to the devices of FIGS. 2, 8 and 9. FIG. It is also possible to combine at least part of the structure of FIG. 8 and at least part of the structure of FIG. 9 into one element.

In the embodiments of FIGS. 1, 2 and 8-10, the thickness of the active layers A10, A11, A12, A15, A20 is also several hundred nm or less, eg about 300 nm or less. The thicknesses of the active layers A10, A11, A12, A15, and A20 are as thin as about 50 nm or less, about 30 nm or less, or about 10 nm or less. For example, in FIG. 1, if the thickness of the active layer A10 is thin, the distance between the first charge density change region 10 and the second charge density change region 20 is shortened, which is advantageous for improving and controlling light modulation characteristics. can act. The thicknesses of the first dielectric layer D10, the second dielectric layer D20, and the intermediate dielectric layer D15 are, for example, several nanometers to several hundreds of nanometers, but are not limited thereto. Also, the thicknesses of the first dielectric layer D10, the second dielectric layer D20 and the intermediate dielectric layer D15 can be made different from each other.

When the light modulation elements described with reference to FIGS. 1, 2, 8 to 10 are referred to as 'unit elements', a plurality of unit elements can form an array structure. Examples are illustrated in FIGS. 11-13.

FIG. 11 is a cross-sectional view showing an optical modulator according to another embodiment.

Referring to FIG. 11, a plurality of conductors C10a, C10b, and C10n are spaced apart from each other on a substrate SUB100, and a first dielectric layer D100 covering the plurality of conductors C10a, C10b, and C10n is provided. good too. An active layer A100 may be provided on the first dielectric layer D100, and a second dielectric layer D200 may be provided on the active layer A100. A plurality of nano-antennas N10a, N10b and N10n may be spaced apart from each other on the second dielectric layer D200 and arranged to face the plurality of conductors C10a, C10b and C10n, respectively.

A "signal applying means" configured to independently apply an electrical signal to each of the plurality of conductors C10a, C10b, C10n and each of the plurality of nanoantennas N10a, N10b, N10n may be provided. The signal applying means is also a voltage applying means. Voltages V _B1 , V _B2 , and V _Bn are independently applied to the plurality of conductors C10a, C10b, and C10n, respectively, and voltages V are independently applied to the plurality of nanoantennas N10a, N10b, and N10n, respectively. _T1 , V _T2 and V _Tn are also applied. At this time, the active layer A100 may be grounded.

A plurality of first charge density change regions 10a, 10b, 10n are formed in the active layer A100 by voltages V _B1 , V _B2 , V _Bn independently applied to the plurality of conductors C10a, C10b, C10n, respectively. . A plurality of second charge density change regions 20a, 20b, 20n are formed in the active layer A100 by voltages V _T1 , V _T2 , V _Tn independently applied to the plurality of nano-antennas N10a, N10b, N10n, respectively. . The plurality of first charge density change regions 10a, 10b, 10n are arranged adjacent to the first dielectric layer D100, and the plurality of second charge density change regions 20a, 20b, 20n are arranged adjacent to the second dielectric layer D200. may be placed adjacent to the The charge densities of the plurality of first charge density change regions 10a, 10b, 10n and the plurality of second charge density change regions 20a, 20b, 20n are independently controlled.

One conductor (e.g. C10a), its corresponding nano-antenna (e.g. N10a), and the active layer A100 region located therebetween constitute one unit element, e.g., a unit cell. A plurality of such unit elements (cells) may be arranged in the light modulation element. Different voltages are applied to at least two of the plurality of conductors C10a, C10b, and C10n, and independently, different voltages are applied to at least two of the plurality of nanoantennas N10a, N10b, and N10n. I do too. Voltages applied to any one of the plurality of conductors C10a, C10b, and C10n and nano-antennas corresponding thereto may be different from each other. The phase modulation of light generated by each of the plurality of unit elements can be independently controlled. By appropriately controlling the phase modulation of light by the plurality of unit elements, the direction of beams emitted therefrom can be steered. For example, if the phase modulation generated by the plurality of unit elements arranged in the first direction is controlled to decrease by π/2 in increments along the first direction, the light reflected by the plurality of unit elements Direction is controlled (steered) in a particular direction. It can be said to be an optical phased array type of beam steering. By adjusting the phase change rule of the phase array, the light steering direction can be adjusted in various ways.

Although the above discussion exemplifies that the reflected light is steered in one direction, it is also possible to steer the light in different directions in different regions, allowing for some beam shaping. be. For example, the light modulating element may include a plurality of regions each having a plurality of cells, and beam shaping to a desired form is possible by steering the beam in a different direction for each of the plurality of regions. be.

According to this embodiment, the phase modulation of light generated from a plurality of unit elements (cells), in other words, generated by a plurality of nano-antennas N10a, N10b, N10n may differ by up to 360°. Moreover, even if the phase changes, the reflectance (%) of the plurality of unit elements (cells) is generally maintained at a constant high level. Therefore, light modulation efficiency is improved, and noise and distortion problems can be suppressed/prevented.

FIG. 12 is a cross-sectional view showing an optical modulator according to another embodiment.

Referring to FIG. 12, a plurality of second active layers A20a contacting the plurality of conductors C10a, C10b, C10n, respectively, are interposed between the plurality of conductors C10a, C10b, C10n and the first dielectric layer D100; A20b and A20n may also be provided. In other words, a plurality of second active layers A20a, A20b, A20n are provided in contact with the plurality of conductors C10a, C10b, C10n, respectively, and the first dielectric layer D100 includes the plurality of conductors C10a, C10b, C10n, and It may be provided to cover the plurality of second active layers A20a, A20b, and A20n. Third charge density change regions 30a, 30b, 30n are formed in the plurality of second active layers A20a, A20b, A20n, respectively. The second active layers A20a, A20b, A20n and the third charge density change regions 30a, 30b, 30n correspond to the second active layer A20 and the third charge density change regions 30 described with reference to FIG. 8, respectively.

FIG. 13 is a cross-sectional view showing an optical modulator according to another embodiment.

Referring to FIG. 13, at least two active layers may be provided between the first dielectric layer D100 and the second dielectric layer D200. Here, two active layers, that is, a first active layer A110 and a second active layer A120 are provided, and an intermediate dielectric layer D150 is further provided therebetween.

A first active layer voltage V _A1 is applied to the first active layer A110, and a second active layer voltage V _A2 is applied to the second active layer A120. Optionally, one of the first active layer A110 and the second active layer A120 may be grounded. Voltages V _B1 , V _B2 , and V _Bn are independently applied to the plurality of conductors C10a, C10b, and C10n, respectively, and voltages V are independently applied to the plurality of nanoantennas N10a, N10b, and N10n, respectively. _T1 , V _T2 and V _Tn are also applied. A plurality of first charge density change regions 11a, 11b, 11n and a plurality of second charge density change regions 21a, 21b, 21n are formed in the first active layer A110. A plurality of third charge density change regions 31a, 31b, 31n and a plurality of fourth charge density change regions 41a, 41b, 41n are formed in the second active layer A120. The unit structure of FIG. 13 corresponds to or is similar to the structure of FIG.

A light modulation element according to an embodiment of the present application may include a plurality of unit elements arranged one-dimensionally or two-dimensionally. FIG. 14 illustrates a case where a plurality of unit elements are arranged one-dimensionally, and FIG. 15 exemplarily illustrates a case where a plurality of unit elements are arranged two-dimensionally.

Referring to FIG. 14 , a plurality of conductors (conductive elements) 120 are arranged one-dimensionally apart from each other in a first direction, for example, the Y-axis direction, and a plurality of nanometers facing the plurality of conductors 120 . An antenna 200 may be provided. An active layer 160 spaced apart from the plurality of conductors 120 and the plurality of nano-antennas 200 may be provided. A first dielectric layer 140 may be provided between the plurality of conductors 120 and the active layer 160, and a second dielectric layer 180 may be provided between the active layer 160 and the plurality of nanoantennas 200. .

Voltage applying means for applying a voltage independently to each of the plurality of conductors 120 and each of the plurality of nano-antennas 200 may be provided. For example, the voltage applying means may be a first voltage applying means V B for applying a voltage to the respective conductor 120 and the active layer 160, and a first voltage applying means V _B for applying a voltage to the respective nanoantenna 200 and the active layer 160. of second voltage application means _VT . Active layer 160 may be grounded.

It can be said that the light modulation element according to this embodiment is a case where a plurality of unit elements of FIG. 1 are arrayed one-dimensionally. In that case, a device for steering the beam in a one-dimensional direction can be implemented. In other words, by differently controlling the optical modulation (phase modulation) characteristics generated by a plurality of unit elements, it is possible to one-dimensionally control the steering direction of the beam by combining them.

Referring to FIG. 15, a plurality of conductors (conductive elements) 120 may be arranged two-dimensionally, for example, in the X-axis direction and the Y-axis direction, separated from each other. A first dielectric layer 140 covering the plurality of conductors 120 may be provided, an active layer 160 may be provided on the first dielectric layer 140, and a second dielectric layer 180 may be provided on the active layer 160. good. A plurality of nano-antennas 200 may be provided on the second dielectric layer 180 . The plurality of nanoantennas 200 may be arranged to face the plurality of conductors 120 .

Although not shown, each of the plurality of conductors 120 may be provided with voltage applying means for applying a voltage independently. Also, each of the plurality of nano-antennas 200 may be provided with voltage applying means for applying voltage independently. At this time, the active layer 160 may be grounded.

It can be said that the light modulation element according to the present embodiment is a case in which a plurality of unit elements of FIG. 1 are arrayed two-dimensionally. In that case, a device for steering the beam in two-dimensional directions can be implemented. In other words, by controlling the light modulation (phase modulation) characteristics generated by a plurality of unit elements differently in the X-axis direction and the Y-axis direction, the steering direction of the beam is two-dimensionally controlled by the combination thereof. can be done.

In FIG. 15, the plurality of nanoantennas 200 may have a structure extended (continuous) in a predetermined direction, eg, the X-axis direction. Moreover, the plurality of conductors 120 can also have a structure extending (continuously) in a predetermined direction, for example, the X-axis direction. An example is illustrated in FIG.

Referring to FIG. 16, a plurality of conductors 120L may be spaced apart from each other. The plurality of conductors 120L may have a structure extending in the X-axis direction, and they are separated from each other in the Y-axis direction. A first dielectric layer 140 covering a plurality of conductors 120L is provided, an active layer 160 and a second dielectric layer 180 are sequentially provided on the first dielectric layer 140, and a plurality of dielectric layers 180 are provided on the second dielectric layer 180. of nanoantennas 200L may be provided. The plurality of nano-antennas 200L may have a structure similar to the plurality of conductors 120L, extended in the X-axis direction, and separated from each other in the Y-axis direction.

In the above embodiments, the case where one nano-antenna is provided corresponding to one conductor (conductive element) has been mainly described, but according to another embodiment, one conductor (conductive element) may be provided with a corresponding plurality of nano-antennas. One example is illustrated in FIG.

Referring to FIG. 17, a plurality of conductors (conductive elements) 125 may be provided on the substrate 100 while being spaced apart from each other. A first dielectric layer 140 covering the plurality of conductors 125 may be provided, and an active layer 160 and a second dielectric layer 180 may be provided on the first dielectric layer 140 in sequence. A plurality of nano-antennas 200 may be provided on the second dielectric layer 180 . Two or more nano-antennas 200 may be arranged corresponding to one conductor 125 . Accordingly, each conductor 125 can have a size (width) that covers two or more nanoantennas 200 .

A voltage applying means (not shown) for applying a voltage independently to each of the plurality of conductors 125 and each of the plurality of nano-antennas 200 may be provided. The active layer A160 may be grounded. Alternatively, the active layer A160 may further include other voltage applying means (not shown) for applying a predetermined voltage. A plurality of first charge density change regions 16 are formed in the first layer region (lower layer portion) of the active layer 160, and a plurality of second charge density change regions 26 are formed in the second layer region (upper layer portion) of the active layer 160. is formed.

It can be said that one conductor 125, two or more corresponding nano-antennas 200, and the area therebetween constitute one unit area R1. In each conductor 125, the area corresponding to the nanoantenna 200 can act as an effective electrode area. Therefore, the first charge density change region 16 is formed in the portion corresponding to the effective electrode region. A voltage is applied to the conductor 125 in one unit region R1, and different voltages are applied to two or more nano-antennas 200. FIG. Also, the voltage applied to the two or more nanoantennas 200 may be different than the voltage applied to the conductor 125 .

FIG. 18 is a cross-sectional view showing an optical modulator according to another embodiment.

Referring to FIG. 18, a circuit board CS100 may be provided, and an optical modulation device structure according to an embodiment, such as the device structure of FIG. 11, may be provided on the circuit board CS100. Signal applying means for applying electrical signals to each of the plurality of conductors C10a, C10b, C10n and each of the plurality of nanoantennas N10a, N10b, N10n is formed in the circuit board CS100. The signal applying means is also a voltage applying means. As a specific example, the circuit board CS100 is divided into a plurality of cell areas, and each cell area has various configurations such as a 1T (transistor)-1C (capacitor) configuration, a 2T-1C configuration, or a 2T-2C configuration. can have The circuitry of the circuit board CS100 is electrically coupled to each of the plurality of conductors C10a, C10b, C10n and each of the plurality of nanoantennas N10a, N10b, N10n. Such electrical connections are made by connection wires using via holes, bonding wires, etc., which are used in various semiconductor devices. The active layer A100 is also grounded, and a separate voltage applying means for applying a predetermined voltage to the active layer A100 is further provided in the circuit board CS100. On the other hand, in some cases, the substrate SUB100 may be eliminated.

In the above embodiments, the nanoantennas are illustrated simply as an example, but the structure of the nanoantennas can be variously changed.

19A through 19D are perspective views showing various structures/forms of nano-antennas applied to light modulators according to example embodiments.

Referring to FIGS. 19A to 19D, the nanoantenna has various structures such as a circular disk (FIG. 19A), an elliptical disk (FIG. 19B), a cross (FIG. 19C), and an asterisk type (FIG. 19D). / can have the shape A cross shape (FIG. 19C) is also a form in which two nanorods cross each other vertically, and a star shape (FIG. 19D) is also a star (*) shape in which three nanorods cross each other. In addition, although not shown, nanoantennas may be cones, triangular pyramids, spheres, hemispheres, rice grains, rods, fish bones, etc. It can have various deformation structures such as a (fish-bone) structure. Also, the nanoantenna may have a multi-layer structure in which multiple layers are stacked, or may have a core-shell structure including a core and at least one shell. Further, two or more nano-antennas having different structures/forms may form one unit and be periodically arranged.

The resonance wavelength, resonance wavelength width, resonance polarization characteristics, resonance angle, reflection/absorption/transmission characteristics, etc. may vary depending on the structure/form and arrangement of the nano-antenna. Therefore, by controlling the structure/morphology and arrangement of the nano-antennas, it is possible to manufacture an optical modulation element having properties suitable for the purpose.

By using the light modulation device according to an embodiment, it is possible to implement a device that steers a beam in a predetermined direction.

FIG. 20 is a conceptual diagram illustrating a beam steering device including light modulating elements according to one embodiment.

Referring to FIG. 20, a beam steering element 1000A can be used to steer a beam in one dimension. For example, the beam can be steered along the first direction DD1 toward the predetermined object OBJ. Beam steering element 1000A may include a one-dimensional array of multiple light modulating elements according to embodiments of the present application.

FIG. 21 is a conceptual diagram for explaining a beam steering element including an optical modulation element according to another embodiment.

Referring to FIG. 21, a beam steering element 1000B can be used to steer the beam in two dimensions. For example, the beam can be steered along a first direction DD1 and a second direction DD2 perpendicular thereto toward a given object OBJ. Beam steering element 1000B may include a two-dimensional array of multiple light modulating elements according to embodiments herein.

FIG. 22 is a block diagram for explaining an overall system of an optical device including beam steering elements to which light modulation elements are applied according to one embodiment.

Referring to FIG. 22, optical device A1 may include beam steering element 1000 . The beam steering element 1000 may include the light modulating elements described with reference to FIGS. 1, 2, 8-19, etc. FIG. The optical device A1 may include a light source section within the beam steering element 1000 or may include a light source section provided separately from the beam steering element 1000 . The optical device A1 may include a detector 2000 for detecting light steered by the beam steering element 1000 and reflected by an object (not shown). The detection unit 2000 includes a plurality of photodetection elements, and may further include other optical members. Also, the optical device A1 may further include a circuit unit 3000 connected to at least one of the beam steering element 1000 and the detection unit 2000 . The circuit unit 3000 includes an operation unit that acquires and operates data, and may further include a driving unit, a control unit, and the like. Also, the circuit unit 3000 may further include a power supply unit, a memory, and the like.

FIG. 22 illustrates a case where the optical device A1 includes the beam steering element 1000 and the detection unit 2000 in one device, but the beam steering element 1000 and the detection unit 2000 are not provided as one device, and are separately provided. may be provided separately in the device. In addition, the circuit unit 3000 is not connected to the beam steering element 1000 or the detection unit 2000 by wire, but is connected by wireless communication. In addition, the configuration of FIG. 22 varies in many ways.

The beam steering elements according to the embodiments described above are applied to various optical devices. As an example, beam steering elements are applied in lidar (LiDAR) devices. A lidar (LiDAR) device is also a phase-shift or time-of-flight (TOF) device. Such lidar (LiDAR) devices include autonomous vehicles, flying objects such as drones, mobile devices, small walking means (e.g., bicycles, motorcycles, baby carriages, boards, etc.), robots, people / Applied to animal aids (such as walking sticks, helmets, accessories, clothing, watches, bags, etc.), IoT (internet of things) devices/systems, security devices/systems, etc.

23 and 24 are conceptual diagrams showing a case where a lidar (LiDAR) device including a light modulation element according to one embodiment is applied to a vehicle. 23 is a side view and FIG. 24 is a top view.

Referring to FIG. 23 , a lidar (LiDAR) device 51 can be applied to a vehicle 50 to obtain information about an object 60 . The vehicle 50 is also an automobile having an autonomous driving function. A lidar (LiDAR) device 51 can be used to detect a subject 60 including an object or a person in the direction in which the vehicle 50 is traveling. Also, the distance to the subject 60 can be measured using information such as the time difference between the transmission signal and the detection signal. Also, as illustrated in FIG. 24, information can be obtained about near objects 61 and distant objects 62 within the scan range.

Light modulators according to various embodiments of the present application can be applied to various optical devices in addition to lidars (LiDARs). For example, by using the light modulation device according to various embodiments, it is possible to acquire 3D information of space and objects through scanning, so that it can be applied to 3D image acquisition devices and 3D cameras. be done. The light modulating element also finds application in holographic display devices and structured light generating devices. In addition, the light modulating device is also applied to various optical components/devices such as various beam scanning devices, hologram generating devices, optical coupling devices, variable focus lenses, and the like. Light modulation elements are also applied in various fields where "metasurfaces" or "metastructures" are used. In addition, the optical modulation element and the optical device including the same according to the embodiments of the present application are applied to various uses in various fields of optical and electronic equipment.

Although many items have been specified in the foregoing description, they should not be construed as illustrations of specific implementations. For example, those skilled in the art will appreciate that the configurations of the light modulation elements described with reference to FIGS. Will. As a specific example, the active layer in FIG. 11 and the like can be patterned and used for a plurality of active layer elements, and an electrical signal (voltage) can be applied independently to each active layer element. You will know that you can. Also, it will be appreciated that the light modulating element according to an embodiment can be applied not only to a reflective element but also to a transflective element or a transmissive element. Also, it will be appreciated that the application field of the light modulation device according to an embodiment is not limited to the above description, but may be variously changed. Therefore, the scope of rights is not determined by the described embodiments, but by the technical ideas described in the claims.

The optical modulation element and the operating method thereof according to the present invention can be effectively applied to, for example, technical fields related to optical instruments.

A10, A11, A12, A20 active layer C10, C10a-C10n conductor CS100 circuit board D10 first dielectric layer D15 intermediate dielectric layer D20 second dielectric layer N10, N10a-N10n nanoantenna SUB100 substrate V _B , V _T , V1 to V3, V10 to V40 voltage application means 10, 11 first charge density change regions 20, 21 second charge density change regions 30, 31 third charge density change region 41 fourth charge density change region 100 substrates 120, 120L Conductor 140 First dielectric layer 160 Active layer 180 Second dielectric layer 200, 200L Nano antenna

Claims (32)

a nano-antenna,
a conductor;
an active layer disposed between the nanoantenna and the conductor, wherein at least one physical property is changed by an applied voltage;
a first dielectric layer disposed between the active layer and the conductor;
a second dielectric layer disposed between the active layer and the nanoantenna;
signal applying means configured to independently apply a first voltage to the conductor and a second voltage different from the first voltage to the nano-antenna. The signal applying means is
a first voltage applying means for applying the first voltage between the conductor and the active layer;
2. The light modulating element according to claim 1, further comprising a second voltage applying means for applying the second voltage between the active layer and the nano-antenna. 2. The light modulating element according to claim 1, wherein said signal applying means is configured to apply a third voltage to said active layer. 4. The light modulation element according to claim 3, wherein the third voltage is a reference voltage for the first voltage and the second voltage. 5. The light modulation element according to claim 3, wherein said third voltage is a ground voltage. the active layer includes a first charge density change region and a second charge density change region induced by the electrical signal of the signal applying means;
The first charge density change region is provided adjacent to the first dielectric layer, and the second charge density change region is provided adjacent to the second dielectric layer. The optical modulation element according to any one of claims 1 to 5. 7. The light modulation element according to claim 1, wherein the conductor is a lower reflector electrode arranged under the active layer. 8. The light modulation element according to claim 1, wherein the conductor is a metal layer. The active layer is a first active layer,
The light according to any one of claims 1 to 8, further comprising a second active layer in electrical contact with the conductor between the conductor and the first dielectric layer. modulation element. The active layer is a first active layer,
a second active layer is provided between the first dielectric layer and the second dielectric layer;
10. The light modulating element according to claim 1, further comprising an intermediate dielectric layer between the first active layer and the second active layer. the active layer has a multilayer structure including a lower layer and an upper layer;
11. The optical modulation element according to any one of claims 1 to 10, wherein the lower layer and the upper layer contain different materials or have different doping characteristics. the conductor, the first dielectric layer, the active layer, the second dielectric layer, and the nano-antenna constitute one unit element,
12. The light modulating element according to claim 1, having a structure in which a plurality of said unit elements are arranged. 13. The light modulation element according to claim 12, wherein the plurality of unit elements are arranged one-dimensionally or two-dimensionally. 14. The optical modulation element according to any one of claims 1 to 13, wherein a plurality of nano-antennas are arranged for one conductor. 15. The light modulation element according to claim 1, wherein the active layer contains an electro-optic material whose dielectric constant changes according to the electrical signal applied by the signal applying means. 16. The light modulation device of claim 1, wherein the active layer includes at least one of transparent conductive oxide and transition metal nitride. At least one of the first dielectric layer and the second dielectric layer includes at least one of an insulating silicon compound and an insulating metal compound. 3. The optical modulation element according to . The light modulation element adjusts the reflection phase of incident light by simultaneously increasing the first voltage while decreasing the second voltage, or by simultaneously decreasing the first voltage while increasing the second voltage. 18. The light modulation element according to any one of claims 1 to 17, wherein the light modulation element is configured to change . 19. The optical modulation element according to any one of claims 1 to 18, wherein the optical modulation element is configured to change the reflection phase of incident light up to 360°. An optical device comprising the light modulation element according to any one of claims 1 to 19. 21. The optical device of claim 20, wherein the optical device is configured to steer a beam in one or two dimensions using the light modulating element. 22. The optical device of claim 20 or 21, wherein the optical device comprises at least one of a lidar (LiDAR) device, a 3D image acquisition device, a holographic display device, and a structured light generation device. 2. The optical modulation element according to claim 1 , wherein the conductor includes a plurality of conductors spaced apart from each other, and the nano-antennas comprise a plurality of nano-antennas spaced apart from each other. 24. The light modulating element of claim 23 , wherein the light modulating element is configured to induce phase modulation of light reflected by the nanoantenna. The signal applying means applies different voltages to at least two of the plurality of conductors,
24. The light modulating element according to claim 23, configured to apply different voltages to at least two of the plurality of nano-antennas. 23. The signal applying means is configured to independently apply a voltage to each of the plurality of conductors and to independently apply a voltage to each of the plurality of nano-antennas. 3. The optical modulation element according to . a plurality of conductive elements spaced apart from each other;
a plurality of nanoantennas arranged to face the plurality of conductive elements;
an active layer disposed between and spaced apart from the plurality of conductive elements and the plurality of nano-antennas, wherein at least one physical property is changed by an applied voltage;
a first dielectric layer disposed between the active layer and the plurality of conductive elements;
a second dielectric layer disposed between the active layer and the plurality of nanoantennas;
voltage applying means configured to independently apply a voltage to each of the plurality of conductive elements and to apply a voltage to each of the plurality of nano-antennas that is different from the voltage applied to the plurality of conductive elements ; including
a charge concentration change occurring in a first region of the active layer due to a voltage applied independently to each of the plurality of conductive elements; A light modulation element that modulates incident light by using the charge density change that occurs in the second region of (1). The voltage applying means is
It is configured to apply different voltages to at least two of the plurality of conductive elements, and independently apply different voltages to at least two of the plurality of nano-antennas. 28. The light modulating element according to claim 27. the plurality of conductive elements includes a first conductive element and a second conductive element;
the plurality of nanoantennas includes a first nanoantenna corresponding to the first conductive element and a second nanoantenna corresponding to the second conductive element;
The voltage applying means is configured to independently apply a voltage to each of the first conductive element, the first nanoantenna, the second conductive element and the second nanoantenna. Item 28. The light modulation element according to item 27. The plurality of nanoantennas are arranged one-dimensionally,
30. A light modulating element according to any one of claims 27 to 29, characterized in that the light modulating element is arranged to steer a beam in a one-dimensional direction. The plurality of nanoantennas are arranged two-dimensionally,
A light modulating element according to any one of claims 27 to 29, wherein the light modulating element is configured to steer a beam in two-dimensional directions. An optical device comprising the light modulation element according to any one of claims 27-31.

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